I have two sets of time series data which are collected with different time intervals. One is measured every 15 minutes and the other every 1 minute.
The measured variables are oxygen concentration, oxygen saturation and time, all three of which are measured using the two different instruments which have the different time intervals (6 column arrays in total).
I have two times between which I want to find the index's of all the entries at 15 minute intervals in the time column that sit between them.
co=1;
for i = datenum('03/11/2014/10/00/00','dd/mm/yyyy/HH/MM/SS'):datenum('03/11/2014/00/15/00','dd/mm/yyyy/HH/MM/SS')-datenum('03/11/2014/00/00/00','dd/mm/yyyy/HH/MM/SS'):('03/11/2014/16/00/00','dd/mm/yyyy/HH/MM/SS');
u=find(xyl_time==i);
New_O2(co,1)=xyl_o2conc(u);
New_O2(co,2)=xyl_o2sat(u);
v=find(sg_time==i);
New_O2(co,3)=sg_o2conc(v);
New_O2(co,4)=sq_o2sat(v);
co=co+1;
end
however, this does not work. I have narrowed it down and its something to do with the time interval that I'm using. I want it at every 15 minutes, but when I produce the 15 minute interval and then datestr that number, it comes up with '12:15AM'. I think this is causing the problem, but have no idea how to produce just times alone i.e I just want 00:15 not 12:15 not 00:15 AM or PM. just spacings of 15 minutes for my for loop.
Related
I'm new to anylogic and I have a question, how do I solve this: supply of 30 materials every 10 minutes.
runtime: 5 hours.
30 materials every 10 minutes means 3 materials per minute... in anylogic a material is defined as an agent.
you can generate agents in many different ways, the most typical is using the source from the process modeling library in which you put as a rate 3 per minute
Note that this means that your arrivals will follow a poisson distribution...which means you won't get exactly 3 materials every minute, but if you run for 5 hours, the average will be close to that
if you want exactly 30 materials every 10 minutes, you can use arrivals defined by interarrival time, with intervals of 20 seconds
How can I calculate the number of hours between two times, taking into account the change from standard to daylight savings time between them?
I need to determine which crew is working in my customer's plant. There are four possibilities, changing in a known order from one to the next every four days, so the crew pattern recurs every 16 days. I had planned to store a reference time in my database. To calculate the crew, I would calculate the elapsed hours between the reference time and the current time, modulo it by 384, and use crew A if the result is below 96, crew B for 96-192, and so on.
I am pretty sure that in the spring, when an hour is repeated at the time change, the crew shift is 13 hours long, and in the fall, the crew shift is only 11 hours long. My scheme, at least if it relied on timestamp with time zone objects, would be wrong for an hour every shift for half the year.
Thank you.
I know there must be a simple way that I can learn to do this but I cannot imagine how to start. I am tasked with finding a top 10 matching daily wind power time series in a 30-day plus/minus window from the first day in the time series (Jan 1st) matching a single daily wind power time series and it is out of my level of experience in MATLAB. I have successfully done this matching a single time series of the current year with the exact calendar days from previous years, but I need a more robust searching method to find the best correlated time series in a +/- window of time. For example, I'm comparing a 120 day time series (without leap years) with 25 previous years during the same 120-day period (Jan-Apr). The end result will show me the top 10 time series with the years and Julian day or cumulative day listed and a correlation or RMSE value associated with it. My data looks like this arranged in a 365 (days) X 25 (years) array and I thank you very much for your help!
1182573 470528 1638232 2105034 1070466 478257 1096999
879997 715531 1111498 1004556 1894202 1372178 1707984
636173 937769 2119436 742710 1625931 1275567 1228515
967360 1103082 2218855 1643898 1822868 554769 1325642
I have two numbers; dates in Unix Epoch format.
Say I have two Unix Epoch timestamps:
1349422200 = 05/10/2012 08:30
1350489600 = 17/10/2012 17:00
I am able to find out how many days are between the two date/times, no problem.
What I would like to be able to work out is how many of those days are Saturdays or Sundays (Non-Weekdays). I'm sure there has to be an easy way to go about this but I can't for the life of me figure it out without doing a load of for() loops.
Any help greatly appreciated.
Be more specific with your definition of weekend. Do you only want to include whole weekends (the entire 48 hour period of saturday and sunday)? Or does any range of time containing midnight on Friday night/Saturday morning count as a weekend? Do half weekends count as half, or do you round to the nearest whole number?
In any case:
Figure out what comprises a weekend
Find the first and last weekends in your range of time
Find the time difference between them, in days, and divide by 7
Edit: you're seeking the exact amount of weekend time, with no rounding.
First, split the timespan into 3 chunks:
Everything from the beginning of the range up until the first possible Monday morning at midnight
Everything from the end of the previous block up to the last possible Monday morning at midnight
Everything from the end of the previous block to the end of the range
Then calculate the amount of weekend in each block, and sum them up.
The first block will contain no weekend time if it has a length of zero. If it has a length of 48 hours or less, its weekend time will equal its length. Otherwise, its weekend time will be 48 hours.
The middle block's weekend time is its duration multiplied by 2/7 (trivial, since by our restrictions on its start and end, it is a whole number of weeks.)
The final block will contain no weekend time if its duration is less than or equal to five days. If its duration is greater than five days, its weekend time will equal its duration minus five days.
Special cases
If the block contains no monday midnights, consider the second and third blocks to have a length of zero. Find the beginning and the end of the one weekend inside the block (if it exists) and calculate the overlap.
If the block contains exactly one monday midnight, consider the first block the time before it, the second block to be of zero length, and the third block the time after it, and calculate as usual.
I'm sure there are some much faster and less-processor hungry methods to getting around this. But for me this method was good enough and gets the job done.
//$sDateRaw = First day at 00:00 in Unix Epoch
//$eDateRaw = Last day(+1) at 00:00 in Unix Epoch
//86400 = Number of seconds in 1 day
for($i=$sDateRaw;$i<$eDateRaw; $i+=86400){
if(date("N",$i) != 6 && date("N",$i) != 7){
$weekDays += 1;
}
}
//$weekDays = Total number of days excluding weekends
I have a MySQL table with over 6 million records, each with a epoch timestamp. I need to plot all the timestamps across time of day. In other words, I need to see how many timestamps are between 7am and 8am, 8am to 9am, etc - for all 24 hour blocks in day. I do not need them plotted by day of the week or month, just time in the day. Each timestamp is in UTC.
can someone help me?
You could use MySQL's FROM_UNIXTIME function to get date strings from the database, and dump the results into a file, which you can subsequently read into MATLAB. Next, one of the ways to extract the time of day of each record is to use MATLAB's datevec function, to get each component of the date string seperately:
datevec('2007-11-30 10:30:19')
ans =
2007 11 30 10 30 19
For instance, if you read in the data as one long vector with date strings, you could apply datevec to this vector, and subsequently grab the 'hour column' of the resulting matrix. Then, you can make a histogram of the counts using the hist or histc functions, depending on whether you want to specify bin centers or bin edges. If you have an hour column H, something like hist(H, 0:23) should work. The histc function might be a bit more natural for the nature of your data, but is slightly more involved; check the documentation.